Tuesday, February 08, 2005

The Biggest Planetary Anomaly Yet?

Richard Hoagland, after viewing the Cassini spacecraft's exquisite images of Saturn's moon Iapetus, has ventured the seemingly outlandish notion that the moon is not what it appears upon casual inspection. Rather, Hoagland asserts in a new edition to his website, Iapetus is an artificial world -- a literal spaceship masquerading as a crater-pocked moon.

His evidence is a mixed bag of genuine anomaly and overzealous pixel-chewing that supposedly shows indicting structural detail -- despite the inherent limitations of spacecraft image resolution. The latter technique is likely to be drearily familiar to even occasional Enterprise visitors. But there's no denying the eccentricity that forms his model's skeleton.

Iapetus has long been an object of mystery; before visited by robot probes, its "yin-yang" coloration prompted mainstream scientists to wonder if an extraterrestrial intelligence had modified the moon to function as a celestial beacon. And as Hoagland takes pains to note, Arthur C. Clarke's novel "2001: A Space Odyssey" culminates in a psychedelic rendezvous with an alien monolith on Iapetus.

Iapetus' "Great Wall" is visible in this photo taken by the Cassini orbiter.

Cassini's new images -- vastly more refined that its mechanical predecessors' -- show a wall-like uplift that extends across Iapetus' surface, tantalizingly near the moon's equator. And while the European Space Agency has hazarded geological explanations, all seem witheringly quaint compared to Hoagland's reconstruction, which contends the wall isn't the product of natural forces but the work of "god-like" megascale engineers.

And that's not all. Hoagland meticulously notes internal features in the "Great Wall" that appear eerily manufactured, craters and depressions that he interprets as structural decay, and honeycomb-like terrain that bears at least a superficial resemblance to architectural forms.

In this over-contrasted photo, the sun-lit portion of Iapetus reveals an anomalous faceted effect.

Moreover, Hoagland stresses the Saturnian moon's atypical shape; rather than a sphere, Iapetus is a pronounced ellipse. While this could conceivably be the result of tidal forces, celestial mechanics are less suited to explain evident faceting along Iapetus' limb, seen above. Hoagland goes on to liken Iapetus' weird angularity to a sort of cosmic Epcot Center, insinuating a (mostly) hidden interior held together by a vast Platonic tress-work.

What are we to make of this?

Fortunately, many of Hoagland's claims can be verified. For example, the "Great Wall" really is an enigma, not a false unknown. According to a European Space Agency website, "The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The ridge is conspicuous in the picture as an approximately 20-kilometre wide band that extends from the western (left) side of the disc almost to the day/night boundary on the right. On the left horizon, the peak of the ridge reaches at least 13 kilometres above the surrounding terrain. Along the roughly 1300-kilometre length over which it can be traced in this picture, it remains almost exactly parallel to the equator within a couple of degrees. The physical origin of the ridge has yet to be explained."

Hoagland's conspiratorial allusions to H.G. Wells and his implicit assumption that Arthur C. Clarke somehow knew what to expect are less impressive. Nevertheless, there's an element of genuine strangeness on Iapetus that speaks volumes. My hope is that the scientists at Cassini's helm will look closer -- and muster the courage to advance unpopular hypotheses if the evidence warrants.